Super Grass Could Reduce Cows' Methane-Heavy Burps

For years, scientists have been looking for a safe, effective way to keep cows from belching. And it's not because they're concerned about their manners.

Those burps are a significant source of methane, a greenhouse gas that's many times more potent than carbon dioxide. A 1995 study found that each cow produces between 250 and 500 liters of the gas. A tiny amount of that is released through flatulence, but most of it is emitted from their mouths.

In fact, enteric fermentation, as the creation of methane in animals' insides is called, produces about 26 percent of methane emissions in the U.S. -- nearly as much as oil and gas production (29 percent), according to 2015 U.S. Environmental Protection Agency data.

Now, scientists at Denmark's Aarhus University, in partnership with seed company DLF, may have the answer. Through ordinary breeding assisted by genomic selection, they've developed a"supergrass" that could reduce methane emissions because it's easier for the animals to digest, the Danish news publication Berlinske reports.

Torben Asp, a scientist in the university's Department of Molecular Biology and Genetics, said that tinkering with DNA to create a low-methane grass is a simpler and faster route than using conventional methods to produce a hybrid with the desired characteristics.

"It is simply a better diet for the cow, which can utilize the feed more efficiently and therefore does not emit so much methane gas when it burps," he told Berlinske, according to a Google translation.

The scientists said that the new grass could be in use within eight years.

Hopefully, the grass will provide a better solution than all the others that researchers have looked at over the years. As Science News reported in 2015, they've looked at solutions ranging from adding nitrogen to cattle feed -- which reduces emissions by 70 percent, but can harm the animals' red blood cells -- to selectively breeding cows that burp less.

Scientists found it was difficult to breed cows that belch less without interfering with their fertility and overall health.

One experimenter even tried adding a tea extract to cattle feed to curb methane output. The animals rejected it because it apparently tasted bad.

Modern Farmer reported in 2015 that researchers from Pennsylvania State University also have achieved promising results by adding a chemical methane inhibitor called 3-nitrooxypropanol, or 3NOP, to cows' food.

NOTE: An earlier version of this article incorrectly stated that the grass was genetically modified. It was developed through ordinary breeding assisted by genomic selection. We regret the error.